RE: The 'average-down' myth20 Jan 2021 17:45
CSDI, regarding your ‘averaging down’ story, here’s the specific thing that stood out for me:
You bought a tranche of RDSB at 2688p in July 2018. All well and good.
Much later, you added a 2nd tranche at 2061p in Jan 2020 to, in your words, ‘average down’.
Now, adding that second tranche because you were convinced that they were a good investment in their own right at that point in time would have been absolutely logical. But I suggest that to add them purely in order to ‘average down’ would not have been.
The fact that you already owned some RDS at a higher price should not have somehow made the second batch a more compelling investment choice and it should not have influenced you. It may have given you a ‘feel good’ factor to see your average RDS price much lower after the second tranche was purchased but, mathematically, the profit and loss position on each batch is not influenced by the others. For convenience and accounting purposes we may average them together and, hopefully, some batches make a profit to offset the losses of others but the fact remains that each share purchased contributes a profit or loss according to the price difference between buying and selling.
If you average highly profitable shares with loss-makers then you simply average out the performance. The more times you ‘average down’ in this process the worse the overall performance will ultimately be.